Google VP and de facto spokesperson Marissa Mayer is at the Web 2.0 Summit discussing "What Google secretly discovered along the way." Opens with a story about running studies about Google, doing split A/B testing (giving a small group of users a different version of Google — a different font, different buttons, whatever).

One test: Google tried adding more results to the front result page. Traffic dropped by 20%. (A "holy hell" kind of drop.) Marissa realized what was happening: Users getting 30 results instead of 10 were getting their results half a second later. "What users really wanted was, 'Give us more results in the same amount of time.' Speed is a huge component of what happens."

2:30: A Google search runs through many machines between the user query and the result page. The ISP, the index servers, load balancers. But all that happens in a quarter-second.

Google launched a "diet version" of Maps, much smaller and quicker-loading. Traffic jumped by two digits.